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LIAM McHUGH: From the bobsled run, to the curling house, to
the skating and hockey venues, for hundreds of Winter Olympic
athletes the competition heats up on a cold, hard
place: the ice.
KEN GOLDEN: Ice is a really fascinating substance,
and we're very lucky as humans that it has such interesting
and strange properties.
McHUGH: Ken Golden is a mathematician at the University
of Utah. With funding from the National Science Foundation, he
has traveled to Antarctica to collect data on sea ice for
climate studies. Golden explains it's the unique surface of ice
that makes the slide-and-glide of winter sports possible.
GOLDEN: We can run metal blades over the top of it and that's
being made possible by the slipperiness of the surface
of the ice.
McHUGH: Why is ice slippery? The answer begins with water
molecules - made up of an oxygen atom bonded with two hydrogen
atoms. The oxygen end has a negative charge and the hydrogen
end has a positive charge. The opposite charges attract other
water molecules like magnets and form what are called hydrogen
bonds. Molecules in liquid water move about closely, and the
hydrogen bonds are made and broken easily.
GOLDEN: As water approaches the freezing point, the water
molecules will slow down. They're not bouncing around
as much, because there's not as much thermal energy
in the system.
McHUGH: As the molecules slow down and the hydrogen bonds
begin to hold, they form into rigid hexagonal, or 6-sided,
groups that connect into a structure called
a crystal lattice.
GOLDEN: And then these patterns are repeated on
many different layers.
McHUGH: As ice thickens, the bonds within the structure form
in all directions, locking in place and making the ice hard.
Surface molecules, however, can't form rigid bonds above
them and are in a loose, quasi-liquid state, also called
pre-melt. Under a hockey puck or a skater's blade, this layer
acts like a lubricant that allows almost friction-less
movement over ice, just what the athletes need to glide.
TODD PORTER: A lot of it here that we're concerned about is
the quick and the speed of the ice. So anything that's going to
draw on that or create a problem for that, we try to eliminate.
McHUGH: Todd Porter is Facility Manager of the Utah Olympic Oval
near Salt Lake City, home of the 2002 Winter Olympic Speed
Skating events and where the 2014 US Olympic Speed Skating
team trials were held. Porter oversees the production of the
glass-like ice sheets essential for hockey, figure skating,
and speed skating.
PORTER: When you're talking about ice and creating the
fastest, you know, best quality for any athlete, the number one
thing is cleanliness. Any dirt or sediment or anything that's
on the surface or throughout the ice is going to dull blades.
McHUGH: The water for all the ice surfaces at the Oval first
goes through a filtration system that removes impurities before
being applied to a concrete slab. The refrigeration plant
sends a cold brine solution, or salt water, through pipes in the
concrete. Why brine? Salt ions keep water molecules apart so
they don't form hydrogen bonds as easily to become ice. That
means salt water freezes at a lower temperature than fresh
water. The brine solution chills the slab so the layers of
filtered fresh water put over it will freeze solid.
PORTER: So that system allows us to create a nice, clean surface
that has a really good, strong bond, but also has
a fast surface.
McHUGH: The thicker the ice is, the greater the distance between
the freezing brine and the ice surface, so thicker ice means a
warmer - and softer - surface.
GRACIE GOLD: I'm not super picky about my ice when it comes to
exact temperature and feel, but soft and clean is my favorite.
McHUGH: For figure skating, hockey, and short track speed
skating, the ice is about 1 inch thick, but ice surface
temperatures are different - creating the best surface for
deep edges and curved lines, quick stops and
starts, and traction.
JR CELSKI: If the ice is really thick, which we tend to not like
too much, it makes it really bricky and brittle.
McHUGH: Ice on the long track oval is thinner, about
five-eighths of an inch. This means the surface remains colder
and harder, conditions long track skaters need for a
smooth, gliding stride.
BRITTANY BOWE: One thing that I love about ice skating is the
ice is the same for everybody. It's a level playing field and
the best is gonna win.
McHUGH: For these Olympic athletes, being the best
includes conquering the slippery surface of ice.
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